The invention relates to a system for checking the single crossing of a controlled passage in order to prevent several people from penetrating at the same time into a protected area accessed through said passage.
According to the prior art, the access control aimed at preventing the concurrent entrance of several people in a protected area is obtained in one case with an intercepting booth with interlocked doors, hereinafter indicated as “booth” for shortness, combined with a static weighing device. The people penetrated into said booth are weighed and if their weight is less than the weight programmed for triggering the alarm status, the electronic programmed unit said booth is fitted with pilots the opening of the exit door of the booth, thus allowing the weighed people to penetrate into the protected zone. On the other hand, if their weight is more than that programmed, the alarm triggers, the access door to the protected area remains locked in the closed state and an operator inside the protected area is warned, who checks through direct view or through a video system whether inside the booth there is very heavy person or the alarm has been caused by the concurrent presence of several people into said booth.
In the first case, the operator disables the alarm, enables the opening of the access door to the protected area thus allowing the passage and therefore the crossing of the booth itself, then resets the control system, setting it to carry out the check on the following crossing people.
In the second case, on the other hand, the operator disables the lock of the booth access door, asks the people inside the booth to step back and then enter again into the booth one at a time, after the control system has been reset.
Such system, therefore, upon the passage of a person weighing more than the maximum programmed one goes into alarm and temporarily stops the system itself until the operator intervenes; on the other hand, the concurrent passage of several people through the booth is not detected if they are thin and their overall weight is less than the maximum programmed weight.
Such system therefore is imperfect and definitely unsafe. Another system envisages resort to a booth combined with a dynamic weight detector. Such solution analyses the variation over time of the weight resting on the weighing system associated to the booth, from the opening of the access door to the time when said door closes again. Any limits of weight of the people admitted to the passage are excluded. In this case, heavy people can pass without triggering any alarms provided that the system that analyses the variation over time of the weight of the people penetrated into the booth interprets what has penetrated into the booth itself as a single body. Two people that penetrate together and in synchronism or one clinging to the other's shoulders are interpreted as a single person, and the control system allows their passage. It therefore is an unreliable control system. Another technical solution currently used uses an ultrasound system for analysing the volume inside the booth that delimits the controlled passage. In such solution, the system enables the alarm systems if a volume occupied inside the booth is detected that is higher than a programmed value that is assumed to be due to the presence of several people and/or things therein. This technology is the cause of several false alarms both if the person passing carries relatively bulky personal items and if the person passing has a considerable body mass.
On the other hand, such system does not detect the presence into the booth of several people with a fine body, in particular when they are close to each other so as to look like a single body. Such solution therefore is imperfect and unsafe.
A further technical solution uses biometric data readers, normally located inside the booth. During the check, carried out with both booth doors in the closed state, the person inside said booth allows the reading of a personal biometric data by the detection system. The latter checks the matching of the biometric data read with one of those entered beforehand into a database and belonging to the people admitted to the passage, allows the person subject to check to cross said booth and thus the access to the protected area, also when he/she is with other people, ill intentioned or not, that can therefore penetrate into the protected area without being checked.
It therefore is an unsafe system, such as when the person enabled to access the protected area is hostage of ill intentioned persons that follow him/her armed.
In yet another case the booth is fitted with magnetic card reader. The card contains the data of the person it has been assigned to, among which in some cases his/her weight too, in that case requiring that the access control booth is fitted, besides a card reader, also with a weighing unit. Such solution should check that the crossing of the controlled passage occurs only by the card holder person. In the practice, however, it does not check whether the person passing actually is the one the card has been assigned to or it is another person with almost the same build.
The known control systems therefore are not satisfactory since they give rise to several false alarms, in some cases they allow unchecked persons to access the protected area at the same time as others, in other cases they allow access to persons other than those authorised. For this reason several managers of protected areas that must be accessed by people with single crossing, give up known control systems and make resort to the use of specific personnel in charge of the check, even if this requires very high management costs.